Projection apparatus.



PATENTED NOV. 114, 1907.

E. BAUSOH. PROJECTION APPARATUS.

APPLIOATION FILED APR. 25,1907.

Wikfi V U I ED STATES PATENT v EDWARD BAUSCH, OF ROCHESTER, NEW YORK, ASSIGXOR'TO BAUSCH & -LO.\I B OPTICAL COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

PROJECTION APPARATUS.

To all whomit 'mayconcern:

Be it known thatI, EDWARD Bauscn, of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Projection Apparatus; and I do hereby declare the following to be a full, clear, and exact description of the same,

reference being had to the accompanying drawings,-

forining a part of this specification, and to the referencenumerals marked thereon.

My present invention relates to improvements in apparatus adapted to project enlarged images of various objects or view slides onto a suitable screen, and for use in connection with lectures or other illustrative purposes.- In this type of apparatus, there is employed an illuminator, the light rays from which pass through a condensing lens system to and through the projection device, and the object of the invention is to provide an improved means for ventilating the space in front of the rear lens of the system, so as to cool the rear lens.

. A. further object is to provide a lens element in which the lenses may be readily removed and replaced in order to facilitate cleaning, or for other purposes.

With these and other objects in view, the invention consists of the parts and combinations of parts illustrated-in the accompanying drawings, described in the specification, and more particularly pointed out in the appended claims.

In the drawings: Figure 1 is a side elevation, partly in section, of iaprojection apparatus to which the inventionis shown applied. Fig. 2 is an axial section through the rear lens-element of the condensing lens system, and Figs. 3, 4 and 5 are detail perspective views of the tube and its two lens-retaining rings, re-

spectively.

Referring more particularly to the drawings, A indicates a base or optical bench of a projection apparatus, on which bench is adj ustably mounted, in any suitable manner, a. suitable projection device B connected by a condensing lens system C to an illuminator D.

The illuminator D is in the form of a casing or hood 1 having suitably supported therein a lamp 2 of any suitable type.- The "condensing lens system 0, herein shown, comprises a front lens-element 3 of any suitable form, a rear lens-element and a water chamber 4 interposed between the front lens-elernent and the rear lenselement. I i

The rear lens-element is connected to the casing 1 of the illuminator D and embodies a tubular member 5 a plurality of lenses 6 and 7 arrangedtherein, those shown being respectively, a meniscus, and a plane-convex lens. To support the lenses within the tube, the rear end of the latter is provided with an an nular-intumed flange 8 formed with seats for the rear or -meniscus lens6,;the se seats being made b'y stamping projections or fingers 9 from the metal of" the flange.

Specification of Letters Patept. Application filed April 25. 1907. Serial lie- 370.200.

' PatentedNov. 12,1907.

To hold the meniscus lens 6 to its seat-9 while permitting it to be easily removed, there is provided a retaining ring 10 which tightly and slidingly fits the inner wall of the tube and has struck up therefrom, fingers 11 adapted to engage the convex face of the lens 6, and being preferably three in number 'in order that they may automatically center the lens without requiring attention from the manipulator. This retaininging 10 acts as a spacing member for the lenses, and carries a seat 12 for the other or plane-convex lens 7, said'seat being preferably in the form of an annular inwardly-turned flange on the front end of the retaining ring. The plano-convex lens is held on its seat by a second retaining-ring-l3 which engages the said plano-conveig lens near the periphery, and in addition is provided with fingers 14 struck up therefrom and sprung inwardly into engagement with the convex face of said lens 7. To hold, this latter retaining-ring-lfa within the tube there are provided friction devices or spring fingers 15 also struck up from the said retaining-ring, and sprung outwardly to frictionally-engage the inner wall of the tube 5. The retaining ring 10 is of such thickness that it does not interfere .with the passage of ligated air though the openings 16, hereinafter described.

It will be noted that the manner in which the lenses of the rear lens element are secured in place, permits front of the rear lens and the casing of the illuminator and permit the escape of heated air from said space, thus maintaining the rear lens in a cooled state.

- Having thus described the invention what I claim is:

1. In a' condensing lens system, a lens element comprising a tube having an lnwardly-extendlng flange adapted to engage a lens, and a retaining ring slldlngly fitting within said tube and having means to engage the lens to hold the latter to the flange.

2. In a condensing lenssy'stem tor projection apparatus, a lens element comprlslng a tube, havlng a lens seat formed therein, a retaining ring fitted within said tube, adapted 'to engage a lens on the seat and provided with a lens-seat, and a retaining ring for a lens held on the latter lens-seat.

3. In a condensing lens system, a. lens element comprising a lens tube, a lens seat in said tube, a lens for the seat,

a-ring having means to engage the lemon the seat, a sec: ond lens seated against the ring. and a ring holding the latter lens in place and provided with trlctlon devices to 1 engage the wall of the'tube. Y I I 4. In afcondensing lens system,-a lens element comprislng a lens tube having an inwardly-extending flange, anda retaining ring having inwardly-extending fingers to center the lens on theflange.

'5. In a condensing lens system, a lens element comprisgay,

in; a lens tr be having a lens seat therein, and a retaining ring having spaced devices to center the lens on its seat.

B. In a condensing lenssvstem, a lens element comprisin a tube. an inwardly-extending flange arranged within the use and having openings, a lens seated on the flange and surrounded by the openings, and a retaining device for the lensv 'i In a condensing lens-system, a lenselement compris log a tube. an inwardly-extending flange arranged within the tube and having openings-:1 lens seated on the flange and surrounded by the openings, and a retaining device for the lens, said device comprisinga ring fitting within the tube and having inwardly-extending fingers engaging the lens.

I 15 8.. In a condensing lens-system, a tube; a lens seated in amass the tube, and a retaining ring having fingers frictionally engaging theinner wall of the tube.

9. In a co'ndenslng lens system for projection apparatus, 

